Index Scan retrieves all the rows from the table. Index Seek retrieves selective rows from the table.
SQL SERVER – @@IDENTITY vs SCOPE_IDENTITY() vs IDENT_CURRENT – Retrieve Last Inserted Identity of Record
SELECT @@IDENTITY It returns the last IDENTITY value produced on a connection, regardless of the table that produced the value, and regardless of the scope of the statement that produced the value. @@IDENTITY will return the last identity value entered into a table in your current session. While @@IDENTITY is…
Read MoreSQL SERVER – SQL Commandments – Suggestions, Tips, Tricks
Few days ago, while searching for something on web site, I came across a very good article of 25 SQL Commandments. I really enjoyed reading it. It was for Oracle, I re-wrote it for SQL Server. First 18 points are taken from original article and last 2 I added to…
Read MoreSQL SERVER – DBCC command to RESEED Table Identity Value – Reset Table Identity
DBCC CHECKIDENT can reseed (reset) the identity value of the table. For example, YourTable has 25 rows with 25 as last identity. If we want next record to have identity as 35 we need to run following T SQL script in Query Analyzer. DBCC CHECKIDENT (yourtable, reseed, 34) If table…
Read MoreSQL SERVER – Primary Key Constraints and Unique Key Constraints
Primary Key: Primary Key enforces uniqueness of the column on which they are defined. Primary Key creates a clustered index on the column. Primary Key does not allow Nulls. Create table with Primary Key: CREATE TABLE Authors ( AuthorID INT NOT NULL PRIMARY KEY, Name VARCHAR(100) NOT NULL ) GO…
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SQL SERVER – ReIndexing Database Tables and Update Statistics on Tables
SQL SERVER 2005 uses ALTER INDEX syntax to reindex database. SQL SERVER 2005 supports DBREINDEX but it will be deprecated in future versions. Let us learn how to do ReIndexing Database Tables and Update Statistics on Tables.